Filter



\ FILTER Filed March 15, 1944 Inventor QS Attorney Patented Get. 29,:1946 f.

UNrrEp l stares rMen-r form@ Cecil Gordon Vokes, London, England Application March 15, 1944, Serial No. 526,574 lin Great Britain February 8, 1943 6 Claims. (Cl. 183-'71) Y Deeply pleated lter elements are now used in a variety of forms to give a large filtering area in a relatively small space. Commonly a somewhat stiff material or combination of materials is used, so that joints can be made with the elements and pleats will retain their shape, with the help of spacing means when necessary. For instance, wire gauze has been used to vsupport felt or other textile material, or fibrous material between layers of buckram or other sti cloth; and other forms include several thicknesses of wire gauze, either pleated together or with intermediate layers of the filtering material. The present invention is designed to give a deeply pocketed lor pleated effect with such and other appropriate materials, particularly in cases where the depth of the pockets isto be very great relatively to the cross-sectional area of the inlet or outlet. vIn the pleating,

normal elements at present formed by bends or folds face the inlet and outlet; there is a bend or fold between the mouths of adjacent pockets. In arrangements according to the present invention the bends or folds run the other way, lso that in effect the pleated or bent material surrounds three sides ofeach pocket and adjacentwalls are joined between the mouths of adjacent pockets, where entry (or exit)v of the fluid is blocked, preferably by securing the edges of the material together. The front and back closed ends of the pockets are thus transverse to the folds of the material and a zig-zag effect is produced in a direction transverseV to the folds. From another point of View a filter element is formed of material folded to include roughly triangularor wedge shaped top sections tapering in one direction alternating with triangularlor wedge -shaped bottom sections tapering in the opposite direction, side wall sections (of parallel or tapered form) separating the top and bottom sections. The terms top, bottom, side and so forth are to be understood in this connection as conveniently indicating relative positions only and not that the element necessarily lies in any particular plane.

Other parts oi the invention are embodied in the examples illustrated by the accompanying drawing. Theparts for which a patent is desired are those delimited by the claims.

In the drawing: v

Fig. 1 is a front perspective view of a lter unit capableof being positioned in a duct or over a desired aperture,

Fig. 2 shows a folded element of filtering maangular sections are seen at 2,

terialv suitable for incorporation in or lters,

Fig. 3 illustrates how filtering material is bent in forming an element, Y ,y

Fig. 4 shows an element located in a duct, Y Fig. 5 is a perspective view of a modified form of the invention showing a pair of filtering strips crimped and about to be assembled into the filter element, Y Y,

Fig. 6 is a perspective sectional View taken substantially upon a plane indicative by the line l- Fig. 5, and Y Fig. 7 is a perspective view of a further modilied form of the invention.

suitabie sans'.

AS shown at Fig. 1 Aa deeply pocketed air-filter unit has a low but Vwide (or high but-narrow). inlet and outlet. The unit includes an element of appropriate ltering material, reinforced with wire gauze, which is folded and corrugated vas described above with the folds or bends lying in substantially what will be the direction of air flow. rIhe front and back of Ithe element are provided with rectangular metal grids I I of which the bars l form clips to fasten together 'the necessary portions of the adjacent edge sections. The front and back bars l are staggered or odset relatively to one anothenras will be obvious from an inspection of Figs. l and 2. The bottom trithe top triangular sections at 3 and the side walls at fl. The folding and bending willbe clearer from Figs. 2 and 3, where the top sections 3 are clearly seen and pairs of the edges of the side walls li to be clipped together by the grids are shown at ar, :cl for a bar of the back grid and y, y for a barv of the front grid.A lIhe walls L4, ll'V can be parallel or tapered and the end edges such as anyangle `desired for a particular application. Itwill .be'see'n that my improvedfllter element comprisesv generally an originally ilat sheet of foramnous filtering material having opposite, upper and lower edges, as viewed in Fig. 3. The upper edge is folded as at 2 and each pair of folds has a bend, such as 2a interposed therebetween. The lower edge is similarly formed with folds 3 alternating with bends 3a and each bend 2a of the upper edge is opposite a fold 3 of the lower edge, while each fold 2, of the upper edge, is opposite a bend 3a of the lower edge. The edge portions extending from each bend, are then secured together to a point closely adjacent contiguous folds, so that each fold at one edge gradually tapers and merges into a bend at the other end. Fig. 4 shows a convenient use of an element or unit according to the invention inand y, y set to clined across a duct, the edges :c and y being angled to lie perpendicular to the walls of the duct. It Will be observed that in addition to one end of each pocket being open, the top or bottom (as the case may be) is also open. The element may be encased on all four sides to form a complete unit as shown in Fig. l. According to the use to be made of it, the upper and lower sides may be apertured or closed. Thus,'in Fig. 1 the upper side may be closed where delivery is to be confined to the back conned to the front grid II the bottom can preferably be of the form shown, but blanked off when in its duct or housing in use: or a removable cover may be fitted. Dust will then readily fall away from the dirty side when the unitis removed for cleaning. By appropriately placing or encasing the unit the top and bottom may be allowed to remain open, e. g. in Fig. 4 the front and bottom of a set of pockets may be open to entering air while the intervening spaces (or reverse pockets) may be open to the clean side, so that practically the Whole area of the filtering material (i. e. all except the extreme edges at front and back) is in use. The casing presses on the folds (with a lining of jointing material if necessary) so that each pocket is preferably approximately rectangular in cross section and tapers back until its wall is secured to that at the mouth of the adjacent reverse pocket. seen in Figs. 5 and 6 the reinforced material or" the unit may be originally crimped into substantially the required form of triangles I2 and i3 alternately facing towards 'the front and towards the back and separated by preferably rectangular'panels I4 which will form the filtering portions through which the air orV other fluid will actually pass. Such form -might incltide two lengths of wire gauze or the like I5 and l@ so crimped, one being relatively reversed so that they intert with a length of filtering cloth or the like between them in the ltering portions but exposed outside the triangular portions to make joint with the casing. `The side walls could be so tapered as to be'themselves substantially triangular as at I1, Fig` 7 and in that'case a grid I8 at the'apex` end is merely a mere flat clamp.

I claim: y 1 Y 1. A filter element formed of filtering material folded to include alternating top and bottom sections of shape roughly triangular or Wedge shaped, the top sections `tapering in` one direction and the bottom sections tapering in the opposite direction, and side wall sections lying between the top and bottom sections and having their edges joined in the front'and back `at the apexes of the triangular top and bottom'sections. 2. A filter element formed of filtering material grid I I and if entry is to be y Veach end t0 form grilles,

folded to include alternating top and bottom sections of shape generally triangular, the top sections tapering in one direction and the bottoms tapering in the opposite direction, side wall sections each joining one edge of a bottom triangular section with the superposed edge of a top section, said side Wall sections having their edges joined in the front and back at the apexes of the triangular top and bottom sections, a casing having spaced parallel bars extending across each said joined side wall section being connected with and extending along, a respective one of said bars.

3. A filter element of filtering material folded to form alternating top and bottom sections, each section being generally triangular in shape, the top sections tapering in one direction and the bottom sections tapering in the opposite direction and generally rectangular side wall sections, one edge of each wall section joining the side edge of a respective bottom section, the other edge of said side wall section joining the edge of the next adjacent top section. Y

4. A lter element as recited in claim 3, said top and bottom sections lying in spaced parallel planes, respectively, a casing in the form of an elongated, hollow parallelopiped having opposite sides open, said element being positioned within said casing with each said plane passing through respective ones of two diaginally-opposite edges of said open sides.

5. An originally at sheet of foraminous material having rst and second opposed edges, said rst edge having alternate folds and bends with the edge portions extending from each bend see cured together toa position adjacent the next adjacent folds, the second edge of said sheet having similar'alternate folds and bends, each bend of said second edge being opposite a foldof said first edge and each fold of said second edge lloeing opposite a bend of said rst edge, each' fold at each edge narrowing into and merging with a bend transversely across said sheet.

6. A filter element Acomprising a sheet of foraminous material havingopposed rst and second side edges, said rst edge being formed with spaced alternate bends and folds, the vtwo edge portions extending from each bend, being secured together from said bend to a point closely adjacent and between two contiguous folds, said second edge having like spaced alternate bends and folds, with the two edge portions extending from each bend being secured together to a point closely adjacent two contiguous'folds, each fold of each said rst and second edges tapering transversely of said sheet into a bend at the-opposite edge. A

CECIL 'GORDON VOKES. 

